This invention relates generally to the creation of a sliding and locking loop of cord, and more particularly to a surgical technique of suturing and the formation of a suture loop that may be tightened and locked.
Suturing is a necessary aspect of virtually any surgical procedure. Numerous techniques of tying sutures have been developed by surgeons over the years to address various applications of sutures. For example, a surgeon's knot, in which an overhand knot is modified to include two wraps of the suture ends around each other, was developed to minimize the amount of slippage in the suture as the second or locking throw of a ligation or approximation of tissue was accomplished. Another knot called a Roeder knot was developed to allow surgeons to place a loop of suture around a vessel for ligation in an endoscopic environment. The Roeder knot is basically a pre-tied slip knot that may be cinched and locked around a vessel or other structure. Many other knots, such as the Weston knot described in U.S. Pat. No. 5,405,352 address various other aspects of the surgical requirements of knots for flexibility, development of hoop stress (tightening of the suture loop), stability and reversibility.
In some cases, the development of a knot in a surgical procedure may require dexterity beyond the capability of the surgeon. This is certainly the case in surgeries such as arthroscopic, laparascopic, or thoroscopic surgery. These procedures are accomplished with the aid of an endoscope, a viewing instrument that can be used in conjunction with specialized surgical instrumentation to detect, diagnose, and repair areas of the body that were previously only able to be repaired using traditional "open" surgery. Access to the operative site using endosurgical or minimally invasive techniques is accomplished by inserting small tubes called trocars into a body cavity. These tubes have a diameter of, for example, between 3 mm and 30 mm and a length of about 150 mm (6 inches). A commonality in these procedures is that the spaces in which the surgeon works are limited, and the tools used for suturing make tying knots difficult at best. Surgeons are accustomed to handling the suture, as knots in open procedures are typically tied and pushed down to the wound using the fingers. In endoscopic procedures, either the knots need to be tied externally to the body and inserted into the body and to the operative site using some kind of knot pushing device, or they need to be tied inside the body using long, clumsy instruments.
Currently, in one known technique, the placement of sutures while using endoscopic techniques involves placing a semi-circular needle, attached to and carrying a suture, into a pair of endoscopic needle holders. These needle holders, which resemble a pair of pliers with an elongated shaft between the handles and the jaws, must be placed down through one of the surgical trocars into the body cavity containing the structure to be sutured. Because of their size, the needles used in these procedures are generally not able to be held in the jaws of the needle driver while being introduced through the operative trocar. The surgeon must hold the suture string in the needle holder jaws, and push the needle holder trailing the needle and suture into the body cavity. The suture and needle combination is dropped in the body cavity, and the needle is then located and picked up and properly positioned in the needle holder jaws. This is a difficult and time-consuming aspect of this current endoscopic technique for suturing. The needle carrying the suture may then be driven by pronation of the wrist, causing rotation of the elongate shaft, and subsequent arcuate rotation of the semi-circular needle.
The current instrumentation requires the surgeon to prepare the needle for penetration of the tissue while the needle is inside the body. This process is a time consuming, and sometimes frustrating exercise in hand to eye coordination, which is complicated by the fact that the surgeon is viewing the three dimensional space inside the body cavity through a two dimensional video monitor.
There have been other attempts to improve the methods of tissue repair. These include the development of staplers and anchoring devices. In response to some of the aforementioned problems in placing sutures in tissues endoscopically, manufacturers have developed tissue staplers. These devices utilize stainless steel or titanium staples that are constructed much like the staples used to hold papers together. The major disadvantage of these kinds of staplers is that they leave metal in the body. For some tissues this is not a problem, however in some procedures, metal staples left within the tissues can be a major hindrance to the healing process.
In orthopedic surgery, many different designs for bone anchors have been developed. These anchors allow soft tissues to be reattached to bone, and simplify the process by removing the need to create a transosseous tunnel. Transosseous tunnels are created in bones to allow suture material to be threaded through and tied across the bony bridge created by tunnels after the suture material has been placed through the soft tissues and tied with conventional knots. Anchors are commonly used in joint re-constructions, and because the metal is contained in the bone, it does not cause a problem with healing.
While endoscopy has certainly found favor with many physicians as an alternative operative modality, the advanced skill set and operative time necessary to become an efficient and practiced endoscopist have proven to be a challenge for a large portion of the surgical community. The cost pressures brought about by large scale patient management (the continued rise and success of health maintenance organizations or HMO's) have also caused the surgical community to cast a critical eye on the overall costs and long-term outcomes of some of the procedures that have been tried via a endoscopic approach. While the laparascopic cholecystectomy (gall bladder removal) has certainly proven its worth in the past 8-10 years, many other procedures have not shown similar cost effectiveness and positive long-term outcomes.
Hence, alternatives have been sought to bridge the gap between skill and equipment intensive endoscopic surgery and more familiar open surgery. As such, under the broad umbrella of "minimally invasive surgery" which would include endoscopic surgery, a relatively new approach called "mini-incision surgery" has begun to emerge. This approach uses the principles of traditional open surgery, along with some of the equipment advances of endoscopy to provide the patient with the best of both worlds.
Perhaps the most visible of these new approaches is the emergence of minimally invasive heart surgery, both for coronary bypass and for valve replacement. Techniques and tools for cardiovascular surgery have begun to be used that allow the heart surgeon to perform procedures through small incisions between the ribs that previously required a massive incision and splitting the sternum to gain access to the heart.
In a similar way, orthopedic surgeons have begun to explore alternatives to the traditional open approach for the many indications requiring reconstruction of some aspect of the shoulder. As was the case when minimally invasive approaches were adopted for knee repair and re-construction, the use of either an endoscope or a "mini-open" approach is gaining in popularity with surgeons, patients and third party payers.
It is an increasingly common problem for tendons and other soft, connective tissues to tear or to detach from associated bone. One such type of tear or detachment is a "rotator cuff" tear, wherein the supraspinatus tendon separates from the humerus, causing pain and loss of ability to elevate and externally rotate the arm. Complete separation can occur if the shoulder is subjected to gross trauma, but typically, the tear begins as a small lesion, especially in older patients.
To repair a torn rotator cuff, the typical course today is to do so surgically, through a large incision. This approach is presently taken in almost 99% of rotator cuff repair cases. There are two types of open surgical approaches for repair of the rotator cuff, one known as the "classic open" and the other as the "mini-open". The "classic open" approach requires a large incision and complete detachment of the deltoid muscle from the acromion to facilitate exposure. Following the suturing of the rotator cuff to the humeral head, the detached deltoid is surgically reattached. Because of this maneuver, the deltoid requires postoperative protection, thus retarding rehabilitation and possibly resulting in residual weakness. Complete rehabilitation takes approximately 9 to 12 months.
The "mini-open" technique, which represents the current growing trend and the majority of all surgical repair procedures, differs from the classic approach by gaining access through a smaller incision and splitting rather than detaching the deltoid. Additionally, this procedure is typically used in conjunction with arthroscopic acromial decompression. Once the deltoid is split, it is retracted to expose the rotator cuff tear. The cuff is debrided to ensure suture attachment to viable tissue and to create a reasonable edge approximation. In addition, the humeral head is abraded or notched at the proposed "soft tissue to bone" reattachment point, as healing is enhanced on a raw bone surface. A series of small diameter holes, referred to as transosseous tunnels, are "punched" through the bone laterally from the abraded or notched surface to a point on the outside surface of the greater tuberosity, commonly a distance of 2 to 3 cm. Finally, the cuff is sutured and secured to the bone by pulling the suture ends through the transosseous tunnels and tying them together using the bone between two successive tunnels as a bridge, after which the deltoid muscle must be surgically reattached to the acromion.
Although the above described surgical technique is the current standard of care for rotator cuff repair, it is associated with a great deal of patient discomfort and a lengthy recovery time, ranging from at least four months to one year or more. It is the above described manipulation of the deltoid muscle together with the large skin incision that causes the majority of patient discomfort and an increased recovery time.
Less invasive arthroscopic techniques are beginning to be developed in an effort to address the shortcomings of open surgical repair. Working through small trocar portals that minimize disruption of the deltoid muscle, a few surgeons have been able to reattach the rotator cuff using various bone anchor and suture configurations. The rotator cuff is sutured intracorporeally and an anchor is driven into bone at a location appropriate for repair. Rather than thread the suture through transosseous tunnels which are difficult or impossible to create arthroscopically using current techniques, the repair is completed by tying the cuff down against bone using the anchor and suture. Early results of less invasive techniques are encouraging, with a substantial reduction in both patient recovery time and discomfort.
However, as will now be described, there are cases where the knots themselves are a hindrance to the healing of the wound. In cases where joint re-constructions are undertaken by orthopedic surgeons, oftentimes the space available within joint is quite limited. This is especially true, for example, in a rotator cuff repair. The knots in the tendon can be bulky and create a painful impingement of the tendon on the bone. Because non-absorbable suture materials are used for these types of repairs, the suture and associated knots are not absorbed into the body, and hence provide a constant, painful reminder of their presence. It would therefore be desirable to develop a system that did not require the traditional knots to secure the suture to the tendon.
So it may be seen that none of the currently extant approaches to the placement and securing of sutures in, for example, rotator cuff surgery have fulfilled all of the surgeon's requirements.
What is needed, therefore, is a new approach for repairing the rotator cuff, wherein suture tension can be measured and adjusted, the suture resides completely below the cortical bone surface, there is no requirement for the surgeon to tie a knot to attach the suture to the bone anchor, and the skill level for correct placement is suitable for practitioners having average ability.